Zhou, J.-X. | Search bioRxiv

bioRxiv2025

Plant coumarins enhance viral pathogenicity by miRNA-mediated apoptosis in insect herbivores

Plant secondary metabolites (PSM) influence the susceptibility of insect herbivores to entomoviruses, but the apoptosis mechanism is not clear. Among plant hosts screened, the level of coumarin is correlated with NPV-mediated mortality, with high coumarin levels associated with high mortality and low coumarin levels with low mortality. Flow cytometry and morphological experiments showed that coumarins increased the apoptosis rate in NPV-infected larvae. miRNA transcriptomic analysis of coumarin-exposed larvae identified downregulation of miR-8 and miR-6497-3p, which negatively correlate with expression of pro-apoptotic kinases MAPK and ASK1. In addition, miR-9c-5p is upregulated, suppressing the apoptosis inhibitor 14-3-3 protein zeta. Our study suggests plant coumarins increase the susceptibility of larvae to NPV through miRNA-mediated regulation of apoptotic pathways. These findings suggest viral biocontrol efforts may be more successful on certain host plants, and provide molecular insight into how plant defense chemicals synergize with entomoviruses to control agricultural pests.

ecology↗

bioRxiv2024

Co-recognition of histone acetylation and H3K4 trimethylation by GTE4-EML complex in Arabidopsis

Although histone acetylation and H3K4 trimethylation (H3K4me3) are well-known histone marks associated with active transcription, how they cooperate to regulate transcription remains largely unclear in plants. Our study revealed that the Bromodomain and Extra-terminal (BET) protein GTE4 binds to acetylated histone and forms a complex with the redundant H3K4me3-binding EMSY-Likeproteins EML1 or EML2 (EML1/2) in Arabidopsis thaliana. The eml1 eml2 (eml1/2) double mutant exhibited a morphological phenotype similar to the gte4 mutant, and most of the gte4-mediated differentially expressed genes were co-regulated in the eml1/2 mutant. Through chromatin immunoprecipitation followed by deep sequencing (ChIP-seq), we found that GTE4 and EML2 co-occupy protein-coding genes enriched with both histone acetylation and H3K4me3, exhibiting a synergistic effect on the association of the GTE4-EML complex with chromatin. The association of GTE4 with chromatin requires both the Bromodomain and the EML-interacting domain. This study identified a previously uncharacterized complex and uncovered how it cooperatively recognizes histone acetylation and H3K4me3 to facilitate gene transcription at the whole-genome level in Arabidopsis.

molecular biology↗